The purpose of this study is to establish breeding systems for producing healthy, Aotus, Saimiri, Saguinus, and Cercopithecus in a consistent manner for research investigators at NIH and other interested scientists. Basic reproductive parameters being studied include duration of gestation, male and female reproductive cycles, accessory sexual organ development, male-female breeding ratios, reproductive hormone serum levels, puberty changes, infant development, and minimum reproductive age.